Pentagon policies and priorities are stuck in a state of limbo as stakeholders await word on who will replace departing defense secretary Robert Gates. Gates stated in an interview that he intended to leave public service in 2011, and many observers have assumed that meant in February or March -- right after he presents the fiscal 2012 budget request to Congress. More recently, there have been rumors that the out-processing of Gates was suspended because he decided to stay a bit longer, but pretty much everybody assumes he'll be gone soon.

Many of the department's top political appointees and military officers are expected to leave in a similar timeframe, creating an ambience in the Pentagon's fabled E-Ring not unlike the air of ominous anticipation pervading absurdist playwright Samuel Beckett's Waiting for Godot.

There's a short list of readily available candidates to replace Gates that includes defense policy chief Michelle Flournoy, former deputy defense secretary John Hamre and retired Senator Chuck Hagel. All three have the necessary gravitas and experience to be credible contenders, but they don't offer the one key thing that the Obama White House has come to value so much in Mr. Gates: insulation against partisan attacks from the Right. Gates developed such strong credentials as a national-security hardliner during the Cold War that he has been able to accomplish some of the key goals of a Democratic defense agenda without generating much backlash from Republicans. For instance, he has terminated big-ticket weapon systems such as the F-22 fighter and promoted an end to military discrimination against homosexuals.

On the other hand, Gates has insisted on maintaining defense spending at a higher level than many Democrats would prefer, so what the White House would ideally like in his successor is a defense secretary who is above partisan reproach but more amenable to budget cuts. There aren't many people in either party that offer both of those qualities in a single person, but the two most obvious candidates are Secretary of State Hillary Clinton and former Chairman of the Joint Chiefs of Staff Gen. Colin Powell.

Powell is one of the most respected figures in American public life, a moderate Republican who probably would like to redeem his public career after the role he played in selling Congress on an ill-conceived war in Iraq. Powell would enable the White House to continue focusing on economic and domestic policy, secure in the knowledge that somebody competent is overseeing military matters. The Democratic electoral base might not like the idea of a second Republican in a row running the Pentagon while a Democrat sits in the White House, but the fact that Powell is African American and an ideological centrist would take the edge off any resentment. And few Republicans would be willing to take Powell on over any military issue.

Secretary Clinton presents more tantalizing possibilities, because there is a long-running rumor that she might replace Joe Biden on the Democratic presidential ticket in 2012 (one version of this rumor has Clinton and Biden switching jobs, with the vice president becoming Secretary of State, a role for which he is arguably better suited than his current position). Clinton would make an excellent defense secretary: she's a born leader, understands defense policy in great detail, and is well-liked among senior military officers -- which is why she was just about the only member of the Obama security team who was not criticized in the Rolling Stone story that did in Gen. McChrystal. She might attract more partisan criticism than Powell from the Right, but few people who take her on live to tell the tale: she is tough as nails. In fact, her biggest drawback from the viewpoint of the White House may be her commanding presence, since she could overshadow the President in public perceptions.

There was much speculation a few months ago about the Clinton-to-the-Pentagon scenario, but that has faded. Right now, the rumor mill is focusing on Gen. Powell. But that begs the question of whether either of these figures wants the job. Senator Reed of Rhode Island apparently was approached about filling the shoes of Secretary Gates, and he declined.

It isn't hard to see why people might shy away from running the Pentagon at a time when military spending is likely to fall. On the other hand, it's hard to say no when the President calls.